Magnetic couple for flowmeters or the like



Aug. 12, 1947. N. BREWER MAGNETIC COUPLE FORFLOWMETERS OR THE LIKE Filed sept. 25, 1945 i2 mw ifi ma. m

Patented Aug. l2, 1947 MAGNETIC COUPLE FOR FLOWMETERS R THE LIKE y Nathaniel Brewer, Newtown, Pa., assigner te Fischer & Porter Company, Hatboro, Pa., a corporation of Pennsylvania Application September 25, 1945, Serial No. 618,539

(Cl. 'i3-'209) 11 Claims.

The present invention relates to a certain new and useful magnetic coupling device and-it relates more particularly to a magnetic coupling device adapted for use with flow meters or other similar devices having a movable element sensitive to variations in a variable condition.

An object of the present invention is to provide a new and improved magnetic coupling device. Another object of the present invention is to provide a magnetic coupling device adapted for use with owmeters or with other similar devices having a movable element sensitive to variatlons in a variable condition. Still another object of the present invention is to provide a new and improved magnetic coupling device for use with a rotameter or the like and which is capable of accurately remotely indicating the position of the rotameter iloat under all ordnary operating conditions. A further object of the present invention is to provide a magnetic couple for a rotameter float or the like which will not lose the float and which will accurately follow the float regardless of sudden movements thereof caused` by surging etc.

Other objects and advantages of the present invention are apparent in the following detailed description, appended claims and accompanying drawings.

It has been suggested in the past to provide magneticcoupling devices for remote indication of the posi-tion of a rotameter iloat or other movable metering element sensitive to variations in a variable condition; as for example, temperature, pressure, rate-of-ilow, etc.

Thus in my co-pending application Serial No. 511,493 iiled November 23, 1943, YI have shown a rotameterwhereinthe metering oat carries a magnet and wherein follower magnets are mounted outside the metering tube upon one end of acounter-Weighted lever so that vertical movements of the rotameter float responsive to variations in the fluid rate-of-ilow through the rotarneter causetilting of the lever; tilting of the lever in turn, operating automatic valve control mechanism tending to rse-establish the predetermined rate-of-ilow.

While this magnetic coupling works satisfectorily under most operating conditions, it has not been entirely dependable when used in uid systems wherein conditions of violent surging occur. ,i

That is, in the conventional magnetic coupling device heretofore employed wherein the movable metering element carries a single magnet (or a body of magnetic material such as iron or ironnickel alloy), the eld of magnetic force which couples the outer lever to the iloat is relatively small. Thus, under conditions of violent surging, the float is apt Ito jump or move suddenly a distance sufficient to break the magnetic couple between the leverl and the iloat. Should this happen, of course, the lever will no longer indicate the position of the float and, as a result, the remote indicating and/or controlling mechanism actuated by the position of the lever will not function properly.

Accordingly, the present invention contemplates a new and improved magnetic coupling device which will positively couple the movable metering element to the follower element under all normal operating conditions and which will prevent breaking of the magnetic couple even under conditions of violent surging or the like.

Generally speaking, the present invention contemplates providing the rotameter oat or other movable metering element with a pair of co-axial elongated bar magnets mounted with their similar poles in juxtaposition and further contemplates providing the follower with one or more magnets having poles magnetically opposite to the juxtaposed poles of the float magnets disposed adjacent the path of travel of said lloat magnets. Thus, for example, the float can be providedwith a pair of co-aXial elongated bar magnets having juxtaposed north poles and the follower can be provided with one or more bar magnets having south poles disposed adjacent the path of travel of the float magnets. in this way, not only do the juxtaposed similar poles of the doat magnets exert a stronger field oi attraction for the opposite poles of the follower magnets but also the outer poles of the follower magnets (being the same as the adjacent poles of the follower magnets) tend to repel the iollower magnets and thereby tend to force the follower magnets along with the float magnets under conditions of .violent Surg-ing.

For the purpose of illustrating the invention, there are shown in the accompanying drawings forms thereof which are at present preferred,

although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized Figure 3 represents a fragmentary horizontal .cross-sectional view generally along the line I-B of Figure 2.

In one embodiment shown generally in Figure 1, I may provide a rotameter having a downwardly-tapered vertical metering tube Il and having inlet and outlet connections II and I2 formed in the lower and upper heads or fittings 8l and Il respectively; the fittings 22 and Il being mounted upon the casing or body I4 of the rotameter so as to permit independent universal horizontal positioning thereof.

The downwardly-opening conical cup-shaped now-constricting head Il of a metering float is disposed within the tube Il; the position of the head Il within the tube I being determined by the rate-of-flow of fluid upward through said tube in a manner well known in the art.

The body I4 may be provided with a window Il to permit observation of the'position of the head Il and suitable calibrations may be provided (either directly on the tube Il or on a vertical scale fastened adjacent said tube) whereby the height of the float can be read oi! (either in arbitrary units or directly in gallons per hour," or "liters per minute," or other suitable units).

An elongated cylindrical extension chamber I1 of non-magnetic material is screw-threadedly attached, as at Il, to the upper fitting Il; a gasket Il providing a fluid-tight seal therebetween.

A plug 20 is screw-threadedly fastened in the upper end of the chamber I1 which communicates, at its lower end, with the metering tube Il so that said chamber I1 is, at all times, filled with the fluid being metered.

The metering float is provided with a thin elongated extension rod 2i which extends upwardly from the head I5 and into the chamber I1. A weight-giving body portion 22 is mounted upon the upper end of the rod 2l: the body portion 22 being provided with a pair of vertically-spaced annular ribs 23 which contact the polished inner wall of the chamber I1 and serve `to'center the body portion 22 relative to said chamber I1. The ribs 23 are tapered to provide line-contact with the chamber I1, thereby to reduce friction and to permit free up-and-down movement of said head I'B and said body portion 22 responsive to variations in rate-flow of fluid through the metering tube I0.

The body portion 22 is of non-magnetic material (as for example, synthetic plastic, or nonmagnetic light-weight metal, etc.). Within the body portion 22 are disposed lower and upper elongated bar magnets 24.and 25 respectively. The bar magnets 24 and 25 are disposed so that their north poles touch each other generally at the center of said body portion while their south poles are generally at their free ends.

A lever 26 is pivotally mounted externally of said extension chamber I1 upon a knife-edge 21 and is provided, at one end, with an adjustable counter-weight 2l for balancing. The other end of said lever 28 carries a follower bar magnet 29 which has its south pole disposed adjacent the extension chamber I1.

The lever 26 carries a sector gea'r 30 which is in mesh with a spur-gear wheel 3| mounted upon a supporting plate 32.

A pinion 33 is also mounted upon the support- 4 ing plate 22 and meshes with the wheel II. An indicating pointer 24 is carried by the pinion I3 and is adapted to be rotated therewith relative to a scale Il.

It is apparent that, when the rotameter oat Il moves, responsive to variations in rate-of-ow.' the body portion 22 and the magnets 24 and 2l will move vertically with it. The force of attraction of the juxtaposed north poles of the magnets 24 and 2l creates a magnetic couple with theadjacent south pole of the follower magnet 29. In this way, a vertical movement of magnets 24 and 2l will result in tiltingV of the lever 2l.

That is. if the normal position of the noat Il and the magnets 24 and 2l is that shown in solid lines in Figure 1, it follows that a downward movement of the float Il and the magnets 24 and 25 to the position shown in dash-dot lines, will result in a counter-clockwise rotation of the lever 2l from the generally horizontal position shown in solid lines to the position shown in dash-dot lines. This will cause a counter-clockwise rotation of the sector gear 2l and a clockwise rotation of the spur-gear wheel Ilv and a counterdlockwise rotation of the pinion Il and the pointer 24.

Conversely, an upward movement of the noat Il and the magnets 24 and 2i would result in a clockwise rotation of the lever 2l and the sector gear 3l. a counter-clockiwise rotation oi the spur-gear wheel 2i and a clockwise rotation of the pinion Il and the pointer I4.

As described above, it is obvious that it is virtually impossible for the follower magnet 22 to "lose the magnets 24 and 2l. This is due in part to the fact that the juxtaposed north poles of the magnets 24 and 26 exert Ya stronger magnetic attraction upon the south pole of the follower magnet 29 than would the conventional single float magnet heretofore employed. This is due in further part to the fact that the south poles at the lower and upper ends of the juxtaposed magnets 24 and 25 tend to repel the south pole of the follower magnet 29 should they approach one another and would th'usdrive the follower magnet back toward the north poles of the magnets 24 and 25.

By way of illustration, suppose both the magnets 24 and 25 and the lever 2l were in their lower position shown in dash-dot lines in Figure 1 and suppose further that due to a momentarily violent surge or increase in rate-of-fiow the float and the magnets 24 and 2l were raised suddenly to the position shown in solid lines in Figure 1. Suppose further that this upward motion of the magnets 24 and 25 was so sudden as momentarily to leave the follower magnet 29 in the lower dashdot position. It is apparent that, if this were y to occur, the south pole of the lower magnet 24 would approach the south pole of the follower magnet 29 and would tend to repel it upward and thus to drive it to the horizontal solid-line position at which it would accurately indicate the position of the metering float Il.

In addition to, or in place of, vthe pointer I4, the pinion 33 could be connected to the transmitter unit of any conventional remote indicating and/or control system for remote indication and/or control of the fluid rate-of-flow. Such a remote indicating system could include an impedance circuit, such as is well lmown in the metering art for causing the rotation of the pinion 3l to be duplicated by another remotelysituated pointer as shown, for example. in Sundh, United States Patent Number 1,052,528.

The automatic flow controller could, for example, befeof the air-operated type shown in my copending application Serial Number 533,972, illed May 3, 1944.

It is obvious that the poles of the iloat magnets and of the follower magnet could .Abe reversed without departing from the spirit of the present invention. That is, the magnets 24 and 25 could be arranged so that their south poles are in juxtaposition and the follower magnet 29 could be arranged so that its north pole is adjacent the juxtaposed south poles of the magnets 24 and 25.

The length of the end-to-end magnets 24 and 25 relative to the length of the'metering tube Il! further guards against accidental breaking of the magnetic couple upon violent surging or the like. That is, as can be seen in Figure l, the magnets 24 and 25 may each have alength equal to or greater than, the useful scale length of the metering tube lo.

If the solid-line position of the metering float in Figure l is assumed to be the normal or average position of the float during use, it is evident that the fioat can move vertically up or down within the metering tube a distance less than the length of one of the magnets 24 and 25. is a result, it is virtually impossible for the magnets 24 and @ti to move up or down from the .solidline position shown in Figure l a distance great enough to cause the follower magnet to lose said magnets 2t and 25. That is, even. if the fiow rate were to drop to the lowest figure registered by the metering float, the south pole of the bar magnet 2t would still be above the original horizontal position oi the follower magnet so that the force of repulsion between the south poles of the magnets 25 and 29 would tend to drive the follower magnet downward to its correct position opposite the juxtaposed north poles of the magnets 24 and 25.

Similarly, if the flow-rate were momentarily t to rise to the highest ligure indicated by the rotameter float, the south pole of the magnet Evi would still be below thev normal horizontal position of the follower magnet 29 so that it would tend to repel the south pole of said follower magnet upward to its correct position opposite the juxtaposed north poles of the magnets 24 and 25.

In Figures 2 and 3 I have shown a modified iorm of the present invention which generally resembles that of Figure 1 except for the fact that, in place of the single follower magnet 29, a pair or follower magnets 36 and 31 are carried at the ends of a generally semi-circular yoke 38 mounted. upon the lever 26.

The follower magnets 36 and 3T are positioned at diametrioally-opposed points external to the extension chamber ll and have their respective south poles disposed adjacent said chamber I1. rl'hus, the magnetic force of the juxtaposed north poles of the magnets 24 and 25 attracts the inner south poles of the two followermagnets 36 and 31 and thereby creates a strong imagnetic couple which further minimizes the possibility of the follower magnets losing the float magnets. Should the south poles of the magnets momentarily lose the juxtaposed north poles of the'float magnets, the south poles of said float magnets will repel the south poles of the follower magnets and drive them back into aligned position with the north poles in the manner described hereinabove in connection with the embodiment of Figure 1.

' poles are in juxtaposition while the magnets iid and 31 could be arranged so that their north poles are adjacent the extension chamber il.

The present invention may be embodied in otherspecic forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as. illustrative and not restrictive, reference being had to the apu pended claims rather than to the foregoing description to indicate the scope of the invention.

Having thus described my invention, I claim as new and desire to protect by Letters Patent:

1. For use with a meter for measuring variations in a variable condition and having an element movable responsive to variations in said variable condition; a pair of end-to-end magnets carried by said element and movable therewith, said magnets having their similar poles disposed substantiallyin juxtaposition, a tiltably-mounted lever, a follower magnet carried by said lever, said follower magnet having one. pole disposed adjacent the path of travel 'of said first-mentioned magnets, said adjacent pole of said follower magnet being magnetically opposite to the juxtaposed similar poles of said first-mentioned magnets, whereby movement of said first-mentioned magnets causes tilting of said lever, and means actuated by tilting of said lever for indicating variations in said variable condition.

2. For use with a meter constructed and arn ranged to measure variations in a variable condition and having an element movable responsive to variations in said variable condition; a pair of co-axial end-to-end bar magnets carried by said element and movable therewith, said magnets having their similar poles disposed substantially in juxtaposition and having their other poles disposed at ltheir free ends, a follower bar magnet having one pole disposed adjacent the path of travel 0i saidiirst-mentioned magnets, said adjacent p`ole of said follower magnet being magnetically opposite to the ljuxtaposed similar poles of said first-mentioned magnets, a counterweighted lever mounting for said follower magnet whereby said follower magnet can move along a generally arcuate path upon movement of said nist-mentioned magnets, said juxtaposed similar poles and said adjacent opposite pole forming a magnetic couple, and means actuated by movement of said lever mounting for indicating the movements of said element.

3. ln a system havinga meter for measuring variations in a variable condition, said meter being provided with an element movable responsive to said variations, and having means for inl tioned magnets, and means" operatively connecting said lever mounting to said indicating meansfor actuating said indicating means responsive to tilting of said lever mounting.

4. In a system having a meter for measuring variations in a variable condition, said meter being provided with an element movable responsive to said variations. and having means for indicating the movements of said element; means for magnetically coupling said element to said indicating means. said coupling means including a pair of co-axial end-to-end bar magnets carried by said element and movable therewith, said magnets having similar poles disposed substantially in move with said first-mentioned magnets to cause' tilting of said lever, and means for actuating said indicating means responsive to tilting of said lever.

5. In a system having a movable primary element and having a movable secondary element; means for magnetically coupling said secondary element to said primary element whereby said secondary element will move responsive to movements of 'said primary element, said coupling means including a pair of` co-axial end-to-end bar magnets carried by said primary element and movable therewith and having similar poles disposed substantially in juxtaposition, a movably mounted follower magnet having a pole disposed adjacent the path of travel of said first-mentioned magnets, said adjacent pole being magnetically opposite to said juxtaposed poles and forming a magnetic couple therewith, and means for actuating said secondary element responsive to movements of said follower magnet.

6. For use with a rotameter having a vertical metering tube and having a metering oat disposed for up-and-down movement responsive to variations in rate-of-ow of fluid through said metering tube a pair of co-axial end-to-end bar magnets carried by said float, said magnets having similar poles disposed substantially in juxtaposition, a. follower bar magnet having one pole disposed adjacent the path of travel of said float magnets, said adjacent pole being magnetically opposite to said juxtaposed poles and forming a magnetic couple therewith, a counter-weighted lever mounting for said follower magnet whereby said follower magnet can move along an arcuate path responsive to movements of saidtloatmagnets, and an indicator operatively connected to said lever mounting and adapted to be actuated upon-tilting of said lever mounting.

'7, For use with a rotameter having a vertical metering tube and having an extension chamber disposed co-axially with said metering tube and having a metering float, said float having a ilowconstricting head portion disposed within said metering tube and having anl elongated body portion disposed within said extension chamber; means .for indicating the position of said metering float, said last-mentioned means including a pair of co-axial end-to-end bar magnets disu posed within said body portion, said magnets having similar poles disposed substantially in juxtaposition, a follower bar magnet mounted outside said extension chamber and having one Dole disposed adjacent thereto, said adjacent pole being magnetically opposite to said juxtaposed poles and forming a magnetic couple therewith, a counter-weighted lever mounting for said follower magnet whereby said follower magnet can move responsive to movements of the float magnets, and means for actuating said indicating means responsive to tilting of said lever mounting.

8. For use in a rotameter having a vertical metering tube and having a meteringr float adapted for up-and-down movement responsive to variations in rate-of-fiow of fluid through said tube and having an indicator; means for magnetically coupling said float to the said remote indicator, said last-mentioned means including a pair of co-axial end-to-end bar magnets carried by said oat and movable therewith, said magnets having similar poles disposed substantially in juxtaposition, and a follower magnet having one pole disposed adjacent the path of travel of the I float magnets, said adjacent pole being magnetically opposite to said juxtaposed poles and forming a magnetic couple therewith, a counterweighted lever mounting for said follower magnet whereby said follower magnet will move responsive to movements of the float magnets, and means fory actuating said indicator responsive to tilting of said lever mounting.

9. For use in a rotameter having a vertical metering tube and having a metering float adapted for up-and-down movement responsive to variations in rate-of-ilow of fluid through said tube and having an indicator; means for magnetically coupling said float to the said re mote indicator, said last-mentioned means including an elongated extension carried by said float and movable therewith, a pair of co-axial end-to-end bar magnets disposed within said extension, said magnets having similar poles disposed substantially in juxtaposition, a follower magnet having one pole adjacent the path of travel of said first-mentioned magnets, said lastmentioned pole being magnetically opposite to said juxtaposed poles and forming therewith a magnetic couple whereby said follower magnet will move with the float extension, and means for actuating said indicator responsive to movements of said follower magnet.

10. For use with a rotameter having a vertical metering tube and having an extension chamber disposed coaxially with said metering tube and having a metering float, said float having a flowconstricting head portion disposed within said metering tube and having an elongated body portion disposed within said extension chamber; means for indicating the position of said metering float, said last-mentioned means including a pair of co-axial end-to-end bar magnets disposed within said body portion, said magnets having similar poles disposed substantially in juxtaposition, the length of each of said end-to-end bar magnets being at least as great as the useful length of said metering tube, a follower bar magnet mounted outside said extension chamber and having one pole disposed adjacent thereto, said adjacent pole being magnetically opposite to said juxtaposed poles and forming a magnetic couple therewith, a counter-weighted lever mounted for said follower magnet whereby said follower magnet can move responsive to movements of the float magnets, and means for actuof said lever mount.

11. In a system having a meter for measuring variations in a variable condition, said meter being provided with an element movable responsive to said variations, and having means for indicating the movements of said element; means for magnetically coupling said element to said indicating means, said coupling means including a pair ofi co-axial end-to-end bar magnets carried by said element and movable therewith, the length o! each of said end-to-end bar magnets being at least as great as the extent of movement of said metering element, said magnets having similar poles disposed substantially in juxtaposition, a follower magnet having one pole disposed adjacent the path o! travel of said iirstmentioned magnets, said adjacent pole being magnetically opposite to said juxtaposed similar poles and forming a magnetic couple therewith, a counter-weighted lever mounting for said Iollower magnet whereby said follower magnet can move responsive to movements of said rst-mentioned magnets, and means operatively connecting said lever mounting to said indicating means for actuating said indicating means responsive to tilting oi' said lever mounting.

NATHANLEL BREWER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,215,129 Edlich Feb. 6, 1917 2,260,516 Gerber Oct. 28, 1941 FOREIGN PATENTS Number Country Date 636,699 Germany Nov. 26, 1932 

